Method of setting and equipping casing in wells and drilling under control



y 17, 1938- R. A. MUELLER ET'AL, 2,117,444

METHOD OF SETTING AND EQUIPPING CASING IN WELLS AND DRILLING UNDER CONTROL Filed Dec. 8, 1954 2 Sheets-Sheet l Fig. 3.

INVENTORS RA. MUELLER BY JRfiwcr-x ATTORNEYS y 7, 1938. R. A. MUELLER ET AL 2,117,444

METHOD OF SETTING AND EQUIPPING CASING IN WELLS AND DRILLING UNDER CONTROL Filed Dec. '8, 1934 2 Sheets-Sheet 2 Fig.4.

INVENTORS R. A MUELL Era J. R

Patented May 17, 1938 UNITED STATES PATENT orrlca METITIOD F EQUIPQPING CAS- A ING CONTROL IN WELLS AND DRILLING UNDER Robert A. Mueller and John Bi Yancey, Houston,

Tex minors to Gray Tool Company, a cor poratlon Application December 8, 1934, Serial No. 756,654

"70mins Our invention relates to the setting 0! casing in deep wells, particularly where a plurality of separate strings of casing are to be set and properly equipped at the upper end thereof.

In setting separate concentric strings of casing which must be cemented at the lower end, the proper hanging of each casing string at the upper end becomes'a problem, and it is customary after each separate string has been set to engage with the upper end' and stretch it upwardly until all slack is taken out of the particular string being handled and then a hanger must be adjusted in position to support the casing.

It is an object of the invention'to provide a means and method of handling the casing whereby it is supported in position before the cementing operation takes place.

It is also an object of our invention to pro vide a method of setting a plurality of strings of easing whereby during equipping of the same no danger of blow out of gas from the well is permitted, the escape of the gas from the well being shut oil at all times.

It is a further object of the invention to provide a support and hanger for separate strings of casing which may be operable through an ordi- ,nary blow out preventer and which is adapted to form a close seal with the supporting head or adapter.

The invention also resides in the particular construction of the hanger through which a seal may be made with the supporting head and with the next adjacent upper supporting structure.

The invention will be more clearly understood from the specification read in connection with the drawings herewith, in which- Fig. 1 is a side elevation of the upper, end of a well casing equipped to carry out our invention.

Fig. 2 is a broken central longitudinal section showing a means for hanging a string of casing within a casing head.

Fig. 3 is a broken side elevation partly in section illustrating the securing of an interior casing string in position and equipped for hanging the tubing therein.

Fig. 4 is a side view partly in elevation and partly in central vertical section showing the apparatus employed in handling the equipment of the well.

Fig. 5 is a central longitudinal section showing a slightly different embodiment of the invention whereby separate strings of casing are supported and sealed in position.

In equipping the well while it is being drilled it is customary to set adjacent the upper end thereof a string of surface casing which may extend downwardly into the well approximately three or four hundred feet. This surface casing shown at i in the drawings is equipped at its upper end with a casing head 2 having lateral connections 3 and 4 thereon for the conducting of fluid to or from the outer casing. The upper end of the casing head, as seenin Fig. 2 particularly, is formed with lateral flanges I for connection with the next upper adjacentsupport or adapter 6. The interior of the casing head has a downwardly tapered seat I to receive the bushing 8 on the next inner adjacent string, of casing. In Fig. 2 we have shown a seal between the flanges 5 and 6 formed by a packing ring 9 of metal engaging within opposite annular recesses in the adjacent flanges.

Above the casing head the well head is equipped ordinarily with a master valve III and a blowout preventer il. These members are secured in the order named one above the other and secured rigidly in engagement by a flange and bolt connection as is common in this type of constructlon. The blowout preventer Ii ordinarily has lateral outlets l2 below the sealing members therein and the upper end of the housing for the preventer is shown as equipped with a belied nipple it through which the drill and drill stem may be inserted.

It is to be understood that while the well is being extended below the lower end of the surface casing the drill and drill stem are operated through the blowout preventer and master valve as shown. If danger of blowout occurs the blowout preventer may be closed and the escape of gas through the drill stem may be prevented by the action of the pumps forcing heavy mud downwardly therethrough. When the drill is to be removed from the well for any purpose the drill stem is'remcved upwardly through the blowout preventer until the drill bit has reached the posi- When the well has been drilled to a depth neces-- sitating the setting of a second string of casing the drill stem and bit are removed as previously stated. The rams or valve members upon the blowout preventer ii are thenchanged to provide rams adapted to seal around the casing which is to be inserted. The first length of casing inserted through the blowout preventer is equipped with a back pressure valve thereon to prevent the escape of fluid upwardly through the same. After the rams have been fitted about the casing the master valve I0 is opened and the string of easing may be inserted downwardly into position for cementing. When the bottom of the well has been reached with the new string of easing the upper end thereof is equipped with a bushing 8, as shown in Fig. 2. Said bushing is threaded on its interior at its upper and lower ends and its outer surface is provided with a downwardly tapered end having packing rings therein to seal against the tapered seat 'I previously described. The bushing is then lowered into its seat, holding the string of casing l5 suspended slightly off the bottom of the well. This string will then hang taut and is ready to be cemented.

The cementing operation including the pumping of the cement downwardly through the string of casing l5 and past the back pressure valve at the lower end is then performed in the usual manner. After the cement is in position the casing-.is the n allowed to stand until the cement has properly set and when this is done the well may be drilled deeper if desired or it may be that the well has already reached the proper depth, in which case the upper end of the well will be equipped for drilling through the plug of cement at the bottom of the well ready for the setting of the strainer. If no further drilling is necessary a plate such as is shown at 16 in Fig. 3 will be employed to engage around the upper shoulder 11 of the bushing 8. This plate may be secured rigidly in position by bolts l8, as shown in the drawings. The pipe I9 is then secured in the upper end of the bushing and a tubing head 20 secured to the upper end oi the section of casing l9. Ordinarily the well is then drilled in and equipped with a tubing hanger 2| for the tubing 22.

It is usually necessary to set several strings of casing and if it is necessary to drill further after the second string of casing l5 has been set, a casing head 23, such as is shown in Fig. 4, for the next string of casing, will be employed. Said casing head has lower and upper flanges 2i and 25 thereon by means of which it may be bolted to the flange 5 upon the casing head and to the flange 26 of the adapter 21 above it.

The casing head 23 rests upon the bushing 8 7 and the joint between the two is sealed with the metallic sealing ring 9. This construction enables the two sealed joints to be tightened simultaneously and at the same time anchors the bushing 8 against displacement. Another advantage is that the area within the sealing ring 9' is somewhat smaller than that within the sealing ring 9 and consequently the tendency for the pressure to separate the two flanges is reduced. This feature is also found in the bushing construction shown in Fig. 5. The casing head has lateral outlets 28 for fluid therefrom, and is sealed with the adjacent members in the same way as has been previously described. In order to accommodate the master valve previously noted, the adapter 21 has its upper end increased in diameter to connect with the lower end 29 of the said master valve III.

In this arrangement the drill stem may be then inserted through the blowout preventer and master valve and the drilling of the well may proceed as before. where another inner string of easing must be set the drill stem and drill are then drawn up and removed through the master valve and blowout preventer, as previously described, the master valve being closed. The inner string of casing is then inserted and cemented as previously described, the bushing 8 of the next inner string being engaged within the tapered seat 30 of the casing head 23. This string of casing will also be cemented in position at the bottom with the weight of the string of easing hanging from the support 30. We are enabled to suspend the weight of the casing upon a bushingof this char- When the proper depth isreached acter in our construction. due to the particulartype of bushing employed, as it will be understood that the bushing 8 is adapted to be passed downwardly through the rams of the blowout preventer and move to its supporting seat, the blowout preventer in the meantime being available to shut off any attempt of the well to blow out. We make our changes from one casing head to the next for drilling the hole for the succeeding string of casing while the cement is plugging the bottom end oi! the well.

In the embodiment shown in Fig. 5,,the bushing 8', upon which the casing string I5 is suspended, is formed to seal with the casing head SI above it. This is accomplished by extending the upper end of the bushing 8' upwardly a short distance and beveling or tapering off the upper end, as shown at 32. Packing rings may then be set in the tapered surface which is adapted to engage with an upwardly tapered inner seat 33 on the casing head 34. I

By the use of this type of hanger 8' no sealing member is necessary between the adjacent flanges of the two casing heads, the seal being accomplished entirely bythe wedging downwardly over the bushing 8' of the casing head 3|. Bolts between the adjacent flanges of the two casing heads may be employed to draw the casing heads into sealing engagement with the hanger bushing. Fig. 5 shows three separate casing heads employed one above the other for the support of three separate strings of easing. At the upper end of the upper casing head 35 we have shown a tubing hanger 36 to support the tubing 31,-which feature forms no part of the present invention.

By the use of our method of setting casing and with our particular type of hanger bushing it is possible to handle the drilling of the well up to the point where the casing has been entirely set without any danger of a blowout from the well. The usual blowout preventer and master valve may be employed as the only necessary device for controlling of the well. Furthermore, by the use of our particular hanger for the casing it is possible to support the casing from its upper end in position for cementing the lower end. This is particularly advantageous in that the casing is thus stretched to its full extent at the time it is set and is held in taut position thereafter. No operation'of engaging and stretching the easing into an erect position is necessary with our method.

What we claim as new is:

1. A method of inserting a plurality of concentric strings of pipe into a well equipped with well casingand casing head; including sealing a string of pipe to prevent entrance of well fluid thereto from the well, providing a temporary seal between said string and casing at the upper end of the well to prevent escape of fluid around said pipe, moving said pipe downwardly-through said seal, hanging said pipe in said casing head and simultaneously forming a permanent seal between the upper end of said pipe and said casing below said temporary seal while said temporary seal is still available, cementing through said pipe string, removing said temporary seal, introducing a drill and drill stem into said pipe string, forming a temporary seal between said pipe string and said drill stem, and drilling through said cement.

2. A method of inserting a plurality of concentric strings of pipe into a well equipped with well casing and casing head; including sealing a string of pipe to prevent entrance of well fluid thereto from the well, providing a temporary seal between said string and casing at the upper end of the well to prevent escape of fluid around said pipe, moving said pipe downwardly through said seal, hanging said pipe in said casing head and simultaneously forming a permanent seal between the upper end of said pipe and said casing below said temporary seal while said temporary seal is still available, cementing through said pipe string, removing said temporary seal, introducing a drill and drill stem into said pipe string, forming a temporary seal between said pipe string and said drill stem, drilling through said cement, and repeating the operation to hang and cement additional concentric pipes.

3. A method of inserting a plurality of concentric strings of pipe into a well equipped with a :asing head, while maintaining control of the well at all times, including sealing an inner string of pipe at its lower end to prevent entrance of well fluid thereto from the well, lowering said string into an outer string of pipe open at its lower end to the well formation, through a temporary seal at the casing head between said outside string and said inside string to prevent escape of fluid upwardly around the latter, hanging said inner string in said casing head and simultaneously forming a permanent seal between the upper end of said inner string and said outer string below said temporary seal while the later is still available, cementing through said inner string, removing said temporary seal, introducing a drill and drill stem into said inner string, forming a temporary sea] at the casing head between said inner string and said drill stem, and drilling through the cement.

4. A method of inserting a plurality of concentric strings of pipe into a well equipped with a casing head, while maintaining control of the well at all times, including sealing an inner string of pipe at its lower end to prevent entrance of well fluid thereto from the well, lowering said string into an outer string of pipe open at its lower end to the well formation, through a temporary seal at the casing head between said outside string and said inside string to prevent escape of fluid upwardly around the latter, hanging said inner string in said casing head and simultaneously forming a permanent seal between the upper end of said inner string and said outer string below said temporary seal while the latter is still available, cementing through said inner string, removing said temporary seal, introducing a drill and drill stern into said inner string, forming a temporary seal at the casing head between said inner string and said drill stem, drilling through the cement, and repeating the operation to hang and cement additional concentric strings of pipe.

5. A method of inserting a plurality of concentric strings of pipe into a, well equipped with a casing head, including lowering an outer string of pipe into the well and cementing the lower end thereof, allowing the cement to set, drilling through the outer string cement while maintaining a seal between said outer string and the drill string at the casing head and providing against upward flow of fluid from the well through the drill string, removing the drill string while maintaining control of the well both through and around the same, sealing an inner string 01' pipe at its lower end to prevent entrance of well fluid thereto from the well, lowering said inner string into said outer string while the latter is open at its lower end to the well formation, through a temporary seal at the casing head between said outer and inner strings to prevent escape of fluid upwardly around the latter, hanging said inner string in said casing head and simultaneously forming a permanent seal between the upper end of said inner string and said outer string below said temporary seal while the latter is still available, cementing through said inner string, removing said temporary seal and allowing said cement to set, and again drilling through the cement while maintaining control of the well both within and around the drill string.

6. A method of inserting a plurality of concentric strings of casing into a well equipped with a casing head while maintaining control of the well at all times, including sealing an inner string of pipe at its lower end to prevent entrance of well fluid thereto, lowering said string into an outer string of pipe open at its lower end to the well formation through a temporary seal at the casing head between said outside string and said inside string to prevent escape of fluid upwardly around the latter, hanging said inner string in said casing head and simultaneously forming a permanent seal between the upper end of said inner string and said outer string below said temporary seal while the latter is still available, cementing through said inner string, removing said temporary seal, attaching a second casing head above said permanent seal, attaching a temporary seal to the second casing head, intros ducing a drill and drill stem into said inner string through said last named temporary seal and drilling through the cement.

7. A method of inserting a plurality of concentric strings of pipe into a well equipped with a casing head, including lowering an outer string of pipe into the well and cementing the lower end thereof, drilling through the cement at the lower end of the outer string while maintaining a seal between said outer string and the drill pipe at the casing head and providing against upward flow of fluid from the well through the drill pipe, removing the drill pipe while maintaining control of the well both through and around same, sealing an inner string of pipe at its lower end to prevent entrance of well fluid thereto from the well, lowering said inner stringinto the said outer string, while the latter is open at its lower end to the well formation, through a temporary seal at the casing head between said outer and inner strings to prevent escape of fluid upwardly around the latter, hanging said inner string in said casing head and simultaneously forming a permanent seal between the inner and outer strings of casing below said temporary seal while the latter is still available, cementing through said inner string, removing said temporary seal, attaching a second casing head above said permanent seal, attaching a temporary seal to said second casing head, and introducing a drill and drill stem into said inner string of casing, and; drilling out the cement at the lower end of the inner string of casing while maintaining control of the well both within and around the drfll stem.

ROBERT A. MUELLER. JOHN R. YANCEY. 

